has catholicism been hammered out as a magic tradition? I read the example of an archangel as a fire spirit. any ideas for the rest of it? (i'm still waiting on my copy of street magic)

Christian Theurgy, I believe it is called. (Going to spell check in a minute.) It's the official "Christian" magic, which means Catholic.

However alot of the time I and my players make up new Christian magic traditions. Technically a tradition is how the person believes his/her magic to work. So while it's harder, it's not out there to have your own tradition. (However the church authorities are likely to watch you closer for heresy if your a member of the church, and it is going to be easier to get tempted away from the straight and narrow.)

Just watch The Exorcist a bunch of times and when the game rolls around start flicking holy water on your friends.

the Theurgy Tradition described in Street Magic as mentioned above, is 'the propper way' to work magic for all members of the catholic pristehood. If you are a follower of the catholic church, but not a priest (by 2070 both genders are possible, iirc), nun or monk, you are free to follow other Traditions (though they will probably rais an eyebrow at many of them), but otherwise you have to stick with theurgy or keep it secret. They are also kind of touchy about illusions and mental manipulations and discourage summoning in general (need special dispensation).

The tradition summons seraphim and servents of the four archangels.

btw, the Tradition is intended for orther christian mage (i.e. orthodox exarchs) as well.

EDIT: Oh, and I like Wounded Ronin´s suggestion very much